The air-fuel ratio (AFR) is a critical component of any internal combustion engine's performance. For diesel engines in particular, understanding and optimizing the AFR during dyno tuning can greatly influence the engine's power, efficiency, and emissions. This article explores the importance of AFR in diesel vehicles undergoing dyno tuning.

Lambda / AFR Table As a quick reference, here are lambda values and their AFR equivalents for different fuels. This is handy to use when looking at a wideband display/gauge that displays a gas scale AFR or just for curiosity’s sake.

2015年2月14日 · In a diesel, too much fuel (a low AFR) means smoke and engine heat. Not enough fuel (a high AFR) means clean running and lower engine temperatures. The following is a guide for tuning diesels. A non-turbo diesel, such as a Toyota Coaster with 1HZ engine, would generally be tuned in between 15-16:1.

2007年6月8日 · Gas powered engines have an AFR of 14.7 for optimum mpg and maximum power is obtained with an AFR between 12 and 13.5. What is the AFR for a diesel engine? Would knowing the AFR of a diesel engine be useful in tuning for fuel economy or power? Not the same for diesels. A quick search should turn up the details. Too much fuel and it is smokey.

In addition to the answer of Mihir Shete: The stoichiometric air / fuel ratio of diesel is around 14,6; but please consider in your modelling, that diesel engines are not running under...

2013年9月2日 · It is possible to increase the average diesel engines power by ~20% by adding fuel to move it from the stock A/F ratio band to the hot end of tuned band. This is band because other factors come into play. A poor injection system will start to smoke at a higher (leaner) A/F ratio, a very good injection system may run at 17:1 while completely clean.

2003年7月28日 · Stoichiometric AFR for diesel fuel is about the same as that for gasoline. "Ideal" AFR depends on what your goals are - but often AFR for a diesel is set in the neighborhood of 28-32 under "typical" part load conditions.

A diesel engine typically starts to produce visible smoke when the Air-Fuel Ratio (AFR) drops below 15-14:1 for a non-turbo engine, and below 16-15:1 for a turbocharged diesel. Unlike petrol engines, which require a precise AFR of 14.7:1 to operate efficiently, diesel engines are more flexible and can run with a range of AFRs.

In the context of internal combustion engines, air fuel ratio (AF or AFR) is defined as the ratio between the mass of air m a and mass fuel m f, used by the engine when running: \[\bbox[#FFFF9D]{AFR = \frac{m_a}{m_f}} \tag{1}\] The inverse ratio is called fuel-air ratio (FA or FAR) and it’s calculated as:

The stoichiometric AFR depends on fuel type- - for alcohol it is 6.4: 1 and 14.5: 1 for diesel. So what is meant by a rich or lean AFR? A lower AFR number contains less air than the 14.7: 1 stoichiometric AFR, therefore it is a richer mixture. Conversely, a higher AFR number contains more air and therefore it is a leaner mixture.